On Fri, 19 Mar 2004 19:10:35 +0100
Oliver Neukum <[EMAIL PROTECTED]> wrote:
> Except that you forgot to initialise the semaphore.
Now actually with a patch for 2.4.
--- linux-2.4.26-pre2/drivers/usb/printer.c 2004-02-26 14:09:58.000000000 -0800
+++ linux-2.4.26-pre2-nip/drivers/usb/printer.c 2004-03-19 11:43:50.000000000 -0800
@@ -222,6 +222,7 @@
static int usblp_set_protocol(struct usblp *usblp, int protocol);
static int usblp_cache_device_id_string(struct usblp *usblp);
+static DECLARE_MUTEX(usblp_sem); /* locks the existence of usblp's. */
/*
* Functions for usblp control messages.
@@ -332,7 +333,7 @@
if (minor < 0 || minor >= USBLP_MINORS)
return -ENODEV;
- lock_kernel();
+ down (&usblp_sem);
usblp = usblp_table[minor];
retval = -ENODEV;
@@ -374,7 +375,7 @@
}
}
out:
- unlock_kernel();
+ up (&usblp_sem);
return retval;
}
@@ -404,15 +405,13 @@
{
struct usblp *usblp = file->private_data;
- down (&usblp->sem);
- lock_kernel();
+ down (&usblp_sem);
usblp->used = 0;
if (usblp->present) {
usblp_unlink_urbs(usblp);
- up(&usblp->sem);
} else /* finish cleanup from disconnect */
usblp_cleanup (usblp);
- unlock_kernel();
+ up (&usblp_sem);
return 0;
}
@@ -1101,17 +1100,16 @@
BUG ();
}
+ down (&usblp_sem);
down (&usblp->sem);
- lock_kernel();
usblp->present = 0;
usblp_unlink_urbs(usblp);
+ up (&usblp->sem);
if (!usblp->used)
usblp_cleanup (usblp);
- else /* cleanup later, on release */
- up (&usblp->sem);
- unlock_kernel();
+ up (&usblp_sem);
}
static struct usb_device_id usblp_ids [] = {
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